Astronomy 101 Exam 1 Study Guide
The apparent visual magnitudes of four stars are listed below. Of these four stars, which one appears dimmest in the sky? -0.5 +0.7 +2.8 It cannot be determined from the given information. -1.2
+2.8
Which magnitude star is brightest?
-1
Time Between Moon Phases. About how many whole-number days must elapse between first-quarter moon and third-quarter moon?
14 days
If a planet has an average distance from the sun of 31 AU, what is its orbital period in years?
173 years
Rotation, Revolution, Night Sky. Approximately how many times will Earth rotate in one-half revolution around the Sun? Express your answer as a whole number.
183
Uranus orbits the sun with a period of 84.01 years. What is its average distance from the sun in AU?
19
If on March 1st the full moon is near the star Spica, when will the moon next be full?
29.5 days (synodic period)
How many times larger than the moon is the diameter of Earth's umbral shadow at the moon's distance? (Hint: See the image above.) It is _____ times the moon's size.
3
Arc Minute. You observe two stars in the sky and measure their angular distance as 60 degrees. How many arc minutes is this angular distance?
3600 arc minutes
Rotation and Revolution. Approximately how many times will Earth rotate in one non-leap-year revolution around the Sun? Express your answer as a whole number.
365
Assuming your latitude is 40° north, what is the angle between the north celestial pole and the northern horizon?
40°
The amount of time between two solar eclipses visible from the same location is about
54 years.
Angular Distance I. If you are visiting Santa at Earth's geographic North Pole, what is the angular distance from the horizon to the north celestial pole?
90 degrees
For a latitude of 40° north, what is the angle between the southern horizon and the noon sun at the summer solstice?
90° - 40° + 23.4°
What can be said about the maximum duration of lunar and solar eclipses?
A lunar eclipse can last up to almost six hours, and a solar eclipse up to 7.5 minutes.
What does Kepler's second law indicate about the orbital speed of a planet?
A planet moves at its fastest when it is closest to the sun.
Every star is part of a constellation and is assigned a Greek letter within the constellation. Many stars still bear ancient Arabic names. Based on how astronomers refer to stars, select all of the correct statements from the following list. •All 88 constellations are based on figures that originated in Greek and Middle Eastern mythology. •A star with an ancient Arabic name is probably relatively bright. •Only the star of each constellation has an ancient Arabic name. •If a star has an ancient Arabic name, it must be an star. •The modern constellations have English names rather than Latin like the ancient ones. •The star in a constellation is usually brighter than the star. All stars are part of some constellation.
A star with an ancient Arabic name is probably relatively bright. The α star in a constellation is usually brighter than the β star.
If you lived on Mars, which planets would exhibit retrograde motion? Saturn Uranus Neptune Jupiter
All of these choices are correct.
The Milankovitch hypothesis proposes that the ice ages on Earth are due to long-term changes in the amount of seasonal solar heating brought about by which of the following? changes in the shape of Earth's orbit precession of Earth's rotational axis changes in the tilt angle of Earth's rotational axis changes in the shape of Earth's orbit and precession of Earth's rotational axis All of these choices are correct.
All of these choices are correct.
If, one-half revolution ago, you saw Leo in the night sky, which constellation in the figure below will someone at your latitude but on the other side of the world see tonight in his or her night sky, assuming that sky is also clear?
Aquarius
Who taught that the Earth is stationary and at the center of the universe with the sun, the moon, and the planets moving around Earth in perfect circles?
Aristotle (384-322 BC)
The phases of Venus observed by Galileo support the model of the universe presented by which of the following?
Aristotle and Claudius Ptolemy
Kepler's Second Law, Orbital Velocity I. In the figure below, Kepler's second law is depicted. A planet moves from A'→B' in one month and from A→B in one month. Path A to B is longer than path A'→B'. Using this information, along which path is the planet traveling faster?
A→B
The diagram below shows a view of the eastern horizon (horizontal line --------) with the direct eastern horizon point labeled B. The direction to points northeast of the direct east point is labeled with an A and an arrow. The point southeast of the direct east point is labeled with a C and an arrow. A B C ------------------EAST------------------ For a mid-latitude northern hemisphere observer, what point corresponds to the rising point of the sun on the date of the autumnal equinox?
B
The diagram below shows a view of the eastern horizon (horizontal line --------) with the direct eastern horizon point labeled B. The direction to points northeast of the direct east point is labeled with an A and an arrow. The point southeast of the direct east point is labeled with a C and an arrow. A B C ------------------EAST------------------ For a mid-latitude northern hemisphere observer, what point corresponds to the rising point of the sun on the date of the vernal equinox?
B
Below is a postage stamp with a picture of a scientist holding an astronomical model. Who developed this theoretical model?
Copernicus
Why did Copernicus use epicycles in his system?
Copernicus insisted on circular motions and needed epicycles to reproduce minor variations in motions of planets.
Copernicus changed the place of Earth by devising a heliocentric model of the cosmos. Based Copernicus and the heliocentric system, select all of the correct statements from the following list.
Copernicus's model featured multiple motions of Earth. Copernicus's heliocentric model provided a simple explanation for retrograde motion.
Based on how the positions of the moon, sun, and Earth create the right conditions for total and partial lunar eclipses to occur, select all of the correct statements from the following list.
During a lunar eclipse, the moon passes into Earth's shadow. The moon appears red during a lunar eclipse due to scattering of sunlight by Earth's atmosphere.
How did Claudius Ptolemy account for the retrograde motion of the planets?
Each planet moves on an epicycle that in turn moves on a deferent that circles around Earth.
Which of the "First Principles of Ancient Astronomy" did Kepler's laws contradict?
Earth is at the center of the universe and all heavenly motion is uniform and circular.
What is responsible for the observed motion of a star along the celestial equator?
Earth's rotation on its axis
Based on how the positions of the moon, sun, and Earth create the right conditions for lunar and solar eclipses to occur, select all of the correct statements from the following list.
Eclipses do not occur every month because the moon is not always on the ecliptic during the necessary phases. Eclipses occur in a repeating pattern that astronomers can use to predict when they will occur.
Who accurately determined the size of Earth by considering sun angles at Syene and Alexandria?
Eratosthenes (c. 200 BC)
Evidence of how the ancients described the placement of Earth is found partly through archaeostronomy, the study of the astronomy of ancient peoples, and through history beginning with the ancient Babylonians and Greeks. Based on ancient astronomy, select all of the correct statements from the following list.
Eratosthenes accurately estimated the diameter of the Earth. Classical philosophers believed that Earth did not move. Classical philosophers believed that Earth was the center of the universe.
Newton's Second Law II. Two equal body masses are accelerated, but Body A's acceleration is half of Body B's. What is the force of Body B on Body A. Please round the answer to the nearest integer.
FB/FA= 2
Which of the following scientists was condemned by the Catholic Church?
Galileo
Galileo made many observations about the heavens, and was also condemned by the Church. Based on his discoveries and the case against him, select all of the correct statements from the following list.
Galileo's trial was more about his disrespect of authority than his teachings of astronomy. The observed phases of Venus supported the heliocentric system. Galileo's case has recently been reexamined by the Catholic Church. Galileo observed craters on the moon and sunspots on the sun.
Based on this figure, in what constellation is the sun on July 1 each year?
Gemini
How was Tycho Brahe able to make more accurate astronomical measurements than had been made before his time?
He designed and used large devices to measure small angles.
What effect did Plato's proposal have on future astronomers?
His idea of a sphere being the most perfect geometric form influenced astronomical theories for literally hundreds of years.
Total Eclipse Cycles. A total eclipse of the Sun was visible from Canada on July 10, 1972. In which year will this eclipse occur next?
In 2026
How did Nicolaus Copernicus account for the retrograde motion of the planets?
Inner planets orbit the sun faster and pass outer planets as they orbit around the sun.
In Tycho's model of the universe, the moon and the sun orbited Earth, and all the planets orbited the sun. Which of the following is true for the explanation of the phases of Venus in Tycho's model?
It agrees with Galileo's telescopic observations, because Venus at times is farther away from Earth than the sun.
How did Kepler's first law of planetary motion alter the Copernican system?
It changed the perfect circles to ellipses and it placed the sun at one focus of each orbit.
Due to Earth's elliptical orbit, Earth is a little closer to the sun in January than in July.
It is a little cooler than in the southern hemisphere.
What is true of the Saros cycle?
It is an exact number of months.
In Tycho's model of the universe, the moon and the sun orbited Earth, and all the planets orbited the sun. Which of the following is true for the explanation of the phases of Venus in Tycho's system? It matched Galileo's telescopic observations. It did not match Galileo's observations. It was the same as in the Ptolemaic system. Actually, the Tychonic system had no explanation for the phases of Venus.
It matched Galileo's telescopic observations.
Which of the following is true for summer in the northern hemisphere?
It occurs during winter in the southern hemisphere.
Galileo made several important telescopic discoveries. How did Galileo's telescopic discovery of craters on the moon contradict Ptolemaic theory?
It showed that a heavenly body was not perfect.
Galileo made several important telescopic discoveries. How did Galileo's telescopic discovery of sunspots contradict Ptolemaic theory?
It showed that a heavenly body was not perfect.
Galileo made several important telescopic discoveries. How did Galileo's telescopic discovery of the moons of Jupiter contradict Ptolemaic theory?
It showed that not everything orbited Earth.
In 1572, Tycho observed a brilliant "new star," now called Tycho's supernova. What was a result of his failure to detect a parallax shift for this star?
It undermined his belief in the Ptolemaic system, because it meant that the star was far enough away to be part of the "fixed background" of stars, which should be unchanging.
Why did the model of the universe proposed by Copernicus gain support soon after its publication?
It was a more elegant explanation of retrograde motion.
Galileo made several important telescopic discoveries. How did Galileo's telescopic discovery that Venus went through the same cycle of phases as the moon contradict Ptolemaic theory?
It was possible in Copernican theory, but not Ptolemaic theory.
Imagine you are on another planet observing its moon. If the moon orbited the planet in less than a synodic month, which of the following is true?
It would display the same phases as Earth's moon, but cycle through them in less time.
Planet Phases. If you lived on Mars, which planets would never be visible at crescent phases? ________.
Jupiter Saturn Uranus Neptune
Planet Retrograde Motion I. If you lived on Mars, which planets would describe retrograde loops?
Jupiter Saturn Uranus Neptune
Based on Tycho's observations and Kepler's discoveries regarding planetery motion, select all of the correct statements from the following list.
Kepler found that the speed of a planet varied throughout its orbit. Prior to his analysis of the data, Kepler believed there should be a simple relationship between a planet's orbital period and its distance from the sun. Kepler discovered that planetary orbits are elliptical, not circular.
The apparent visual magnitude of star A is 2 and the apparent visual magnitude of star B is 1. Based on this information which statement below must be true? Light output and distance cannot be determined from a star's apparent visual magnitude alone. Star A is closer than star B. Star A emits more light than star B. Star B emits more light than star A. Star B is closer than star A.
Light output and distance cannot be determined from a star's apparent visual magnitude alone.
The 99 years between the deaths of Copernicus and Galileo saw the birth of science in its modern form. Select all of the correct statements from the following list.
Many fields were going through major changes at the time that astronomy and science in general were evolving to their modern forms. Kepler and Galileo were among the first to make scientific predictions based on data analysis and observation. Modern science depends on evidence to test theories. The birth of modern astronomy was also really the birth of modern science.
A Sense of Proportion: Arrange the following in order of increasing distance from the Sun according to the heliocentric theory.
Mercury , Venus , Earth , Mars , Jupiter , Saturn , stars
A Sense of Proportion: Arrange the following in order of increasing distance from Earth according to the geocentric theory:
Mercury , Venus , Sun , Mars , Jupiter , Saturn , stars
Galileo's discovery of four moons orbiting Jupiter showed that planetary bodies could move and carry moons. This supports the model of the universe presented by whom of the following?
Nicolaus Copernicus
If the moon is halfway between the nodes of its orbit, what will occur?
No eclipse will occur.
Which represents an unchangeable truth? a hypothesis a theory a natural law None of these choices are correct.
None of these choices are correct.
The postage stamp below shows the constellation Orion. Why would Orion look odd to residents of the northern hemisphere?
Orion appears upside down!
In 1572, Tycho observed a brilliant "new star," now called Tycho's supernova. Which is true about Tycho's "Tychonic" system?
Planets orbited the sun, which orbited Earth.
A Sense of Proportion: Arrange the following famous scientists in chronological order from first to last:
Ptolemy , Copernicus , Brahe , Kepler , Newton
Which list below has the life and work of the following scientists in chronological order, from left to right?
Ptolemy, Copernicus, Tycho, Galileo
Magnitude System I. Star A has an apparent visual magnitude of 2.5; Star B, 5.5; and Star C, 9.5. Which is brightest?
Star A
Why is Stonehenge thought to be an ancient astronomical observatory?
Stones are aligned with significant rising and setting positions.
A Sense of Proportion: Which of the following are roughly the same angular diameter as seen in the sky? (Select all that are roughly the same). Polaris The Sun The bowl of the Big Dipper The full Moon
The Sun The full Moon
Galileo's telescopes were not of high quality by modern standards. When Jupiter was closest to Earth, he was able to see its disk and moons, but he never reported seeing the disk or features on Mars. What is a good explanation for this difference? (Hints: Use the small-angle formula to find the angular diameter of Mars when it is closest to Earth. How does that compare with the maximum angular diameter of Jupiter? [Assume circular orbits with radii equal to the average distance from the sun.] At its closest, Jupiter is 4 AU from Earth and Mars is 0.5 AU from Earth. Jupiter is 0.000477 AU and Mars is 0.0000226 AU in diameter.)
The angular size of Mars is smaller than the angular size of Jupiter.
It is useful to model the sky as a celestial sphere that rotates around Earth from east to west once per day. Based on the motion of the sky, select all of the correct statements from the following list. The apparent rotation of the sphere is caused by Earth's rotation. At one time or another all of the celestial sphere will be visible from a given location. The celestial equator is a line in the sky directly above Earth's equator. The angular distance between two stars on the celestial sphere is related to the actual distance between them. Precession is literally a wobbling of Earth's rotational axis. The celestial sphere is still useful even though it is no longer accepted as physical reality. The latitude of the north celestial pole is equal to your angular distance from the horizon.
The apparent rotation of the sphere is caused by Earth's rotation. The celestial equator is a line in the sky directly above Earth's equator. Precession is literally a wobbling of Earth's rotational axis. The celestial sphere is still useful even though it is no longer accepted as physical reality.
How does one cycle of the moon's motion relative to the stars compare to one cycle of the moon's motion relative to the sun?
The cycle relative to the stars is shorter than the cycle relative to the sun.
Imagine that Earth did not turn on its axis. What would be true?
The day would be the same length as the year.
We observe that the angular diameter of the moon is about the same as the angular diameter of the sun (about 1/2 a degree). We also know that the distance in AU is about 390 times the average Earth-moon distance. With this knowledge and this figure, what can we conclude about the linear diameters of the sun and moon? (Hint: You do not need the small-angle formula.)
The linear diameter of the sun is about 390 times the linear diameter of the moon.
If a solar eclipse occurs on October 3rd, why can't there be a lunar eclipse on October 10th?
The moon is new on October 3rd and not full until October 17th, the required phase for a possible lunar eclipse.
Which statement below best describes the motion of the moon relative to the stars?
The moon moves eastward relative to the stars about 13° per day.
What did Plato propose about all heavenly motion?
The motion is in circular paths.
The figure shown here illustrates how to draw an ellipse with two tacks and a loop of string. Imagine constructing a new ellipse using the same string but with the distance between the two pins reduced to zero. Which statement below is true?
The new ellipse is a circle.
The motion of the planets observed from Earth is due to their orbits around the sun; some closer than Earth's, some farther away. Based on the motions of the planets, select all of the correct statements from the following list. Astrology is a sister science to astronomy. Mars is never seen high overhead at night. The planets are observed to move approximately along the ecliptic. The closer a planet is to the sun, the longer it takes to move around the ecliptic. Planets generally appear to move westward along the ecliptic. Some planets are too faint to be seen with the naked eye. Planets closer to the sun than Earth can be seen only in the early evening or early morning.
The planets are observed to move approximately along the ecliptic. Some planets are too faint to be seen with the naked eye. Planets closer to the sun than Earth can be seen only in the early evening or early morning.
The figure shown here illustrates how to draw an ellipse with two tacks and a loop of string. Imagine constructing a second ellipse using the same string but with the distance between the two tacks increased by 10%. How does this second ellipse compare to the original ellipse shown here?
The second ellipse is more elliptical than the original ellipse.
Why does the rotational axis of Earth precess?
The sun and moon pull on Earth's equatorial bulge.
What is a reason for winter days being colder than summer days?
The sun is higher in the sky in the summer.
Notice in this figure that the magnitude scale is "awkward" in that the smaller, or more negative, magnitude number corresponds to a brighter star. Why does this scale have this "awkward" direction?
The system was originally set up as a set of classes with first class as the brightest.
In Ptolemy's mathematical model of planetary motion, a planet was on a circular path, known as an epicycle, whose center was on another circular path, a deferent, that was centered on Earth. How did the epicycles of Mercury and Venus differ from those of Mars, Jupiter, and Saturn?
Their centers had to always be on the line between Earth and the sun.
Which statement below most accurately describes modern constellations? They are 13 connect-the-dot mythological sky figures along the ecliptic. They are 88 well-defined regions on the celestial sphere. They are 88 connect-the-dot mythological sky figures. They are 88 groups of stars with members of each constellation physically close together in space. They are 13 well-defined sky regions along the ecliptic.
They are 88 well-defined regions on the celestial sphere.
What is true about stars we say to be on the celestial sphere?
They are all different distances away.
What is true about astronomers?
They use the celestial sphere, a scientific model, to explain motions of the stars.
In Tycho's model of the universe, the moon and the sun orbited Earth, and all the planets orbited the sun. In Tycho's model, the phases of Venus were which of the following?
They were the same as in the Copernican model.
In Tycho's model of the universe, the moon and the sun orbited Earth, and all the planets orbited the sun. Which of the following is true for Galileo's telescopic observation of the phases of Venus?
They were the same as the explanation in two of these models.
When Tycho observed the new star of 1572, he could detect no parallax. Why did that result undermine belief in the Ptolemaic system?
This star is farther away than the moon and thus the heavens are not perfect and unchanging.
A Sense of Proportion: Arrange the following in order of increasing length:
Totality , a lunar eclipse , one revolution of the Moon around Earth , one year , one saros cycle
Whose observatory is shown in the figure below?
Tycho's
If you lived on Mars, which planet would be visible as a crescent phase? Mars Jupiter Venus Saturn Uranus
Venus
Imagine you are on another planet observing its moon. If the moon orbited the planet in an eastward direction and the planet rotated in the same direction, which of the following is true?
You would see the full moon overhead at midnight.
Below is a postage stamp with a picture of a scientist holding an astronomical model. What is the larger circle in his model?
a deferent
Which is an assertion or conjecture that must be tested?
a hypothesis
Galileo's telescope showed him that Venus has a large angular diameter of 61 seconds of arc when it is a crescent; a small angular diameter of 10 seconds of arc when it is nearly full and, finally, when Venus is "half full," an angular size of 59 seconds of arc. At which point described below is Venus closest to the Earth?
a large angular diameter of 61 seconds of arc when it is a crescent
Which is a theory that has been refined, tested, and confirmed so often that scientists have great confidence in it?
a natural law
The quantitative numerical result of Kepler's research was
a set of tables giving future positions of the planets.
Thales of Miletus is thought to have predicted which of the following?
a solar eclipse
Which is a system of rules and principles that can be applied to a wide variety of circumstances?
a theory
In Ptolemy's mathematical model of planetary motion, a planet was on a circular path, known as an epicycle, whose center was on another circular path, a deferent, that was centered on Earth. Which planets' motions were described with epicycles in the Ptolemaic system?
all of the known planets
Below is a postage stamp with a picture of a scientist holding an astronomical model. What is the smaller circle in his model?
an epicycle
Evidence of early prehistoric human cultures observing astronomical phenomena exists in which of the following?
archaeoastronomical sites
At what location on Earth is an observer that has the Celestial Equator pass through the point directly overhead?
at Earth's equator (0° latitude)
In this figure it is apparent that the radius of the precession circle is 23.5°. At what latitude on Earth is the entire precession path currently above the horizon?
at all locations north of 23.5° north latitude
Why did Plato propose what he did about heavenly motion and the shape of heavenly objects?
because he believed the sphere to be the most perfect geometrical form
Why didn't Copernicus's system predict the positions of planets any better than Ptolemy's?
because he used circular orbits
In Ptolemy's mathematical model of planetary motion, a planet was on a circular path, known as an epicycle, whose center was on another circular path, a deferent, that was centered on Earth. Why did the centers of the epicycles of Mercury and Venus have to remain on the line between Earth and the sun?
because they were never seen very far from the sun in the sky
Plato proposed that all heavenly motion is which of the following?
both circular and uniform
Galileo's telescope showed him that Venus has a large angular diameter (61 seconds of arc) when it is a crescent and a small angular diameter (10 seconds of arc) when it is nearly full. When Venus is "half full," its angular size is about 59 seconds of arc. This sequence of phases and angular sizes indicates that Venus:
circles the sun.
What part of the sun is visible during the "peak" of a total solar eclipse?
corona and chromosphere
Gravitational Force, Body A, B I. Body A has the same mass as Body B and is located a distance d from Body B. If Body A is moved further away from Body B by twice as much, did the gravitational force increase, decrease, or stay the same?
decrease
A Sense of Proportion: Arrange the following in order of increasing brightness in the sky:
faintest star visible , Polaris , Sirius , Moon , Sun
Which of these two figures matches the phases of Venus observed by Galileo?
figure b (right)
Look at the Phases of the Moon diagram and visualize yourself on Earth looking at the moon. Which lunar phase would rise in the eastern sky at noon?
first quarter
Identify the phase of the moon if the sun is at its March 21st vernal equinox position and the moon is located at the autumnal equinox point on the ecliptic.
full
Look at the Phases of the Moon diagram and visualize yourself on Earth looking at the moon. Which lunar phase would set in the western sky at dawn?
full
Gravitational Force, Body A, B, C I. If Body A is twice as massive as Body B and both bodies are at the same distance from Body C, is the force of gravity between Body A and Body C greater than, less than, or equal to the force of gravity between Body B and Body C?
greater than
When will the moon will be eclipsed?
if it is at one node of its orbit the same time the sun is at the opposite node
A star's Greek letter designation tells you which of the following?
its relative brightness within its constellation
Newton's Second Law I. Two equal body masses are accelerated, but Body A's acceleration is half of Body B's. Is the force on Body A greater, less than, or equal to the force on Body B?
less than
When does the third quarter phase moon rise?
midnight
A solar-powered spacecraft passed through Earth's shadow. In the outer part of the shadow, the penumbra, what does the spacecraft generate?
more electricity than in the umbra
If you could see the sun and stars during the daytime for several weeks, you would notice that the sun does which of the following?
moves slowly eastward relative to the stars
A total lunar eclipse occurs when the moon is which of the following?
near the ecliptic and at full phase
Draw the Earth's and moon's umbral and penumbral shadows onto a diagram. From a position on Earth in the moon's penumbral shadow, an observer will see a moon phase where the sun is partially covered by a _____ moon.
new
Draw the Earth's and moon's umbral and penumbral shadows onto a diagram. In order to block out the sun, the moon is in which of the following phases as seen from Earth?
new
Imagine you're an astronaut standing on the moon and looking back at Earth. What phase would Earth have when the moon is full as seen by an Earth observer?
new
What phases of Venus are predicted by the Ptolemaic system?
new and crescent phases only
What phases of Venus were observed by Galileo?
new, crescent, quarter, gibbous, and full phases
A Sense of Proportion: Arrange the following in order of increasing length:
one rotation of Earth , one revolution of Moon around Earth , any one of Earth's seasons , one revolution of Earth around Sun , one precession cycle
Which list shows the repeating astronomical cycles or events from the shortest to the longest duration (from left to right):
rotation of the Earth; orbital motion of Earth about the sun; precession of Earth's axis of rotation
During a total lunar eclipse, the moon
s often a reddish color and in Earth's umbra.
A solar-powered spacecraft passed through Earth's shadow. In the outer part of the shadow, the penumbra, what does the spacecraft generate?
some electricity, because it is getting some sunlight, but less than when it is not in Earth's shadow
When it is autumn in Asia, what season is it in Antarctica?
spring
Which set of astronomical tables is based on Ptolemy's model?
the Alfonsine tables
Which set of astronomical tables is based on the Copernican model?
the Prutenic tables
Which set of astronomical tables was developed most recently?
the Rudolphine tables
Which set of astronomical tables were considered most accurate?
the Rudolphine tables
Which set of astronomical tables were worked on by Tycho and Kepler?
the Rudolphine tables
What is the Saros cycle?
the amount of time for the exact pattern of eclipses to repeat itself
Visibility of the solar corona is limited by which of the following?
the brightness of the sun's photosphere
Eclipse Drawings I. Draw a diagram showing Earth, the Moon, and shadows during an annular eclipse. Which has the larger angular diameter: the disk of the Sun, the disk of the Moon, or neither, as both have the same angular diameter?
the disk of the Sun
Which is not an archaeoastronomical site?
the island of Hveen
One of the first principles of ancient astronomy is that the heavens beyond _____ are perfect, and the Earth is corrupt.
the moon
In Ptolemy's mathematical model of planetary motion, a planet was on a circular path, known as an epicycle, whose center was on another circular path, a deferent, that was centered on Earth. What were epicycles used to describe?
the retrograde motion of planets
Below is a postage stamp with a picture of a scientist holding an astronomical model. Which object is the central figure in the model?
the sun
Identify the phase of the moon if at sunrise the moon is high in the southern sky for a mid-northern hemisphere observer.
third quarter
Identify the phase of the moon if the sun is at its March 21st vernal equinox position and the moon is located at the winter solstice point on the ecliptic.
third quarter
Imagine you're an astronaut standing on the moon and looking back at Earth. What phase would Earth have when the moon is at first quarter as seen by an Earth observer?
third quarter
A total eclipse of the sun was visible from Canada on July 10, 1972. When would an eclipse of the sun visible from that part of Canada next occur?
three Saros periods later
What was the most important contribution of Tycho Brahe to modern astronomy?
twenty years of accurate measurements of planetary positions
What feature of Aristotle's model of the universe was included in the model proposed by Copernicus?
uniform circular motion
For a mid-northern hemisphere observer, identify the phase of the moon if at sunrise the moon is in the southwestern sky.
waning gibbous
Which list has the lunar phases shown left to right in the order that they appear during a month?
waxing crescent, first quarter, waxing gibbous, full moon, third quarter, waning crescent
In one cycle of lunar phases, each crescent and gibbous phase has a duration of about one
week.
Based on how stars are named, which star is probably brightest?
α Pegasus
Based on how stars are named, which star is probably brightest?
α Ursae Majoris